Although mental imagery has been shown to have beneficial effects on performance, imagery has been shown to negatively affect physical performances under some conditions. The limited strength model of self-regulation posits that self-control strength is depleted when people regulate their thoughts, impulses, emotions, and behaviours. Research shows depletion of self-control strength in one task domain (e.g., controlling thoughts or images) leads to poorer self-control within similar and dissimilar domains (e.g., controlling physical endurance). The purpose of the present study was to investigate the aftereffects of performing mental imagery on two self-control tasks, physical endurance and response inhibition. Sedentary undergraduates (N = 37) were randomly assigned to either an imagery condition (n = 15), attention-placebo condition (n = 13), or a quiet rest control (n = 9). Participants performed two isometric endurance tasks (30% of maximum handgrip squeeze) separated by their respective study manipulation, and followed by the Wisconsin Card Sort Test (WCST). It was expected that participants in the mental imagery condition would show greater decrements in performance on the second endurance trial (when compared to baseline) and more perseverative errors on the WCST compared to the control conditions. All of the participants’ endurance performances declined over time (p < .05), however, no between group differences were found on endurance performances (p > .05) or on WCST scores (p > .05). Performing a basic 6 minute imagery session involving moderately-intense aerobic exercise does not appear to deplete self-control resources when compared to the attention-placebo and quiet rest control groups. However, the unanticipated decline in the endurance performances observed within the control conditions suggests that future research is needed to better understand the relationship between mental imagery and self-control depletion effects.
©2012 Walter de Gruyter GmbH & Co. KG, Berlin/Boston